From the Journals

Aspirin did not improve sensitivity of fecal immunochemical test



A single oral dose of aspirin did not improve the sensitivity of the fecal immunochemical test to identify advanced colorectal neoplasms in a randomized trial of 2,134 adults.

The study was inspired by an observational study in which the sensitivity of the fecal immunochemical test (FIT) was enhanced in adults taking aspirin for cardiovascular disease prevention.

It was surmised that “aspirin predisposes to subclinical bleeding and, hence, increased detection of advanced adenomas by FIT. This suggests that administration of aspirin prior to fecal sampling might be a practical intervention to increase FIT sensitivity,” wrote Hermann Brenner, MD, of the German Cancer Research Center, Heidelberg, and colleagues.

In a study published in JAMA, the researchers analyzed 2,134 adults aged 40-80 years who were scheduled for colonoscopy. The study participants, who had no recent use of aspirin or other drugs with antithrombotic effects, were randomized to a 300-mg aspirin tablet or a placebo tablet 2 days before stool samples were obtained. The average age of the participants was 60 years, and 78% of the colonoscopies were for primary screening.

Overall, 224 of the study participants had advanced neoplasms, including 216 individuals with advanced adenoma and 8 with colorectal cancer.

Sensitivity was not significantly different between the aspirin and placebo groups at either of two predefined cutoffs of 10.2-mcg Hb/g stool (40.2% and 30.4%, respectively) and 17-mcg Hb/g stool (28.6% and 22.5%, respectively).

Two serious adverse events occurred in the aspirin group but were not considered related to aspirin. No serious adverse events were reported in the placebo group.

Although the results do not support the findings from previous observational studies, they suggest the need for more research of the potential impact of aspirin on FIT sensitivity, the researchers said.

“This trial was designed to detect a 24% absolute increase in sensitivity and was not adequately powered to detect small differences that may nevertheless be clinically meaningful given the low morbidity observed, the low cost of a single dose of aspirin, and the ease of implementation of this intervention across health systems,” they explained.

Additional limitations of the study included lack of adjustment for multiple testing in secondary analyses, inability to analyze subtypes of advanced neoplasms, and the inclusion of only one round of screening. FIT programs usually include multiple rounds, the researchers said. Therefore, “potential effects on detection of advanced neoplasms and reduction of CRC incidence and mortality in the long run are yet to be determined.”

SOURCE: Brenner H et al. JAMA. 2019;321(17):1686-1692.

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